Locally Asymmetric BiOBr for Efficient Exciton Dissociation and Selective O2 Activation toward Oxidative Coupling of Amines

作者：Yu, Linghao; Li, Hao^*; Shang, Huan; Xing, Pan; Zhou, Biao; Chen, Ziyue; Liu, Xupeng; Zhang, Hao; Shi, Yanbiao; Zhang, Lizhi^*

来源：ACS Nano, 2023, 17(15): 15077-15084.

DOI：10.1021/acsnano.3c04268

• photocatalysis
• 2D materials
• symmetry regulation
• selective oxidation
• excitonic effects

Two-dimensional (2D) layered photocatalysts with highlyorderedout-of-plane symmetry usually display robust excitonic effects, thusbeing ineffective in driving catalytic reactions that necessitateunchained charge carriers. Herein, taking 2D BiOBr as a prototypemodel, we implement a superficial asymmetric [Br-Bi-O-Bi]stacking in the out-of-plane direction by selectively stripping offthe top-layer Br of BiOBr. This local asymmetry disrupts the diagnosticconfinement configuration of BiOBr to urge energetic exciton dissociationinto charge carriers and further contributes to the emergence of asurface dipole field that powers the subsequent separation of transientelectron-hole pairs. Distinct from the symmetric BiOBr, whichactivates O-2 into O-1(2) via an exciton-mediatedenergy transfer, surface asymmetric BiOBr favors selective O-2 activation into & BULL;O-2 (-) for a broadrange of amine-to-imine conversions. Our work here not only presentsa paradigm for asymmetric photocatalyst design but also expands thetoolkit available for regulating exciton behaviors in semiconductorphotocatalytic systems.

• 单位
  上海交通大学